U.S. Homeland Security Secretary Janet Napolitano said Friday that providing some kind of legal citizenship pathway and status to illegal immigrants -- which critics say is amnesty -- is key to U.S. national security.

We will never have fully effective law enforcement or national security as long as so many millions remain in the shadows, Napolitano said in a speech Friday to the liberal advocacy group Center for American Progress.

Napolitano said the Obama administration favors immigration reforms that include pathways for the 11 to 12 million illegal immigrants in the U.S. to gain legal status. That includes paying back...